Fluids exiting a vessel tend to swirl and form a vortex, and it is often desirable to minimize the vortex or swirling flow in the exiting fluid. This is particularly true for liquefied natural gas (LNG) and other similar fluids. One way to reduce vortex and swirling flow is to use a breaker at the outlet of the vessel. For example, a vessel 10 illustrated in FIGS. 1A-1C has a basic vaned vortex breaker 30 to reduce vortex and swirling flow in the vessel's outlet 14. As shown, the breaker 30 has vanes 32 welded to the interior of the vessel's wall 12 over the outlet 14. Here, the breaker 30 has four vanes 32 made from two side plates welded to a lager central plate. As the fluid 20 in the vessel 10 flows toward the outlet 14, the flow 22 naturally tends to swirl and form a vortex. However, the vortex breaker 30 over the outlet's mouth 16 is intended to break this tendency and to reduce its ill effects.
Another vortex breaker 40 illustrated in FIGS. 2A-2D fits over a vessel's outlet 14 to reduce the tendency of vortex and swirling flow in the fluid exiting the vessel 10. This type of vortex breaker 40 is similar to that manufactured by Johnson Screen—a Weatherford company. The breaker 40 has a screen basket 41 that fits over several vanes 50. The screen basket 41 has a flat top 42, a cylindrical sidewall 44, a bottom 46, and an outlet insert 48. Both the flat top 42 and cylindrical sidewall 44 are composed of wire screens that have wedged-shaped or profiled wires commonly used in the fluid industry, such as the VEE-WIRES® available from Johnson Screens. (VEE-WIRE is a registered trademark of Weatherford/Lamb, Inc.). As best shown in FIG. 2D, the vanes 50 fit around a central opening 47 in the breaker's bottom 46, and inner and outer rings 52 and 54 can support the upper corners of the vanes 50. This vortex breaker 40 use a baffle plate under the top screen 42.
The basic vaned vortex breaker 30 of FIGS. 1A-1C and the screen breaker 40 of FIG. 2A-2D may be ineffective in some implementations. For example, the basic vaned vortex breaker 30 of FIGS. 1A-1C can be ineffective in LNG applications because properties of LNG tend to produce turbulent flow and/or small vortexes beyond the breaker's vanes 32, producing ill effects in the outlet 14.
In addition, the screen basket breaker 40 with internal vanes 50 of FIGS. 2A-2D must typically have a significantly large size in comparison to the mouth 16 of the outlet 14 to be effective in breaking vortex flow. In some installations, for example, the breaker 40 may need to have a diameter that is about 4 to 5 times the diameter of the outlet's mouth 16, although the actual size may further depend on the fluid type, flow rates, and other variables. The required larger size for the breaker 40 limits its effectiveness in various sized vessels and even limits its use in some situations altogether.
What is needed is a vortex breaker that is more effective for LNG and other types of fluids and that can have a smaller size than conventionally possible.